Effect of pranayama on sympatho-vagal imbalance and cognitive deficit in premenstrual syndrome

ABSTRACT

Context:

Premenstrual syndrome (PMS) is a prevalent and often neglected condition that affects around 80% of women of reproductive age. In PMS, abnormal fluctuations in gonadal hormones cause altered homeostasis, resulting in sympatho-vagal imbalance and poor cognition.

Aim:

To compare autonomic function parameters and cognitive performance between PMS and control groups, and to study the effect of pranayama on the above parameters in PMS women.

Settings and Design:

It was a randomized control trial.

Materials and Methods:

We recruited 40 women of reproductive age who fit the inclusion criteria. They were asked to complete the Premenstrual Syndrome Screening Tool (PSST) questionnaire and were categorized as having PMS (n = 20) or not having PMS (n = 20). All study participants had their baseline CAFT, HRV, BRS, P300, and MOCA values recorded. Following that, participants in the PMS group were divided into two groups of ten at random. For 8 weeks, one group received pranayama training. Following that, all baseline data were recorded again in both the pranayama and no-intervention groups.

Statistical Analysis Used:

SPSS version 20 was used to analyze the data. For parametric data, the unpaired t test was used to compare between the PMS and no PMS groups, whereas the Mann–Whitney U test was employed for non-parametric data. To compare the parameters before and after intervention, the Students paired ‘t’ test for parametric data and the Wilcoxan-signed rank test for non-parametric data were used.

Results:

According to the findings, autonomic function and cognition were considerably affected in the PMS group and improved significantly in the PMS group following pranayama intervention.

Conclusion:

Pranayama is an effective and safe non-pharmacological method for treating PMS and improving women’s quality of life.

Introduction

Approximately 80% of women worldwide have menstrual cycle-related symptoms.[1] PMS occurs when physical, psychological, and behavioural symptoms of premenstrual syndrome (PMS) reoccur cyclically with the luteal phase of each cycle and resolve within a few days after the commencement of menstrual bleeding.[1,2] PMS symptoms can be broadly characterized as physical and psychological, which puts psychiatrists and gynaecologists into the picture in the treatment of PMS.[3] PMS has been documented to have a substantial impact on women’s quality of life, resulting in a stronger psychological impact such as a dislike for menstruation. Previous research has found that PMS lowers economic productivity in working women as well as academic performance in students.[4,5] The menstrual cycle is regulated by gonadal hormones that work together with the hypothalamo-pituitary axis. Gonadal hormones also regulate the activities of the autonomic nervous system in addition to their role in reproductive functions. Oestrogen has been shown to raise vagal tone and decrease sympathetic activity, whereas progesterone has the opposite effect.[6] Increased progesterone levels activate the gene promoting area of Corticotrophin Releasing Hormone (CRH) and the central noradrenergic system, resulting in sympathetic dominance during menstrual cycle’s luteal phase. The pathophysiology of PMS is ascribed to elevated and aberrant amounts of gonadal hormones, which leads to disturbed homeostasis.[7] As a result, the aberrant variation of gonadal steroids in PMS can be related to sympatho-vagal imbalance. Cardiovascular morbidity is predicted by sympathetic-vagal imbalance.[8] To determine sympatho-vagal imbalance, we performed Cardiovascular autonomic function tests (CAFT), power spectrum analysis of heart rate variability (HRV), and Baroreflex sensitivity (BRS), which are the most sensitive tests.[9]

Women suffering from PMS also complain of poor focus, forgetfulness, disorientation, and an inability to think properly.[10,11] Studies have also found that increased progesterone levels cause poorer cognition in normal healthy women across their late luteal phase.[10] The autonomic nervous system interacts with higher mental functions such as cognition, and research shows that enhanced parasympathetic activity improves cognition.[7] In PMS, excessive sympathetic activity in the late luteal phase causes cognitive impairment. P300 is a key component of Event Related Potential (ERP), which is used to test cognition.[12] To test cognition, we used the P300 or Event Related Potentials (ERP) and the Montreal Cognitive Assessment (MOCA) questionnaire[13] in the current study.

PMS-related psychosomatic symptoms have a bigger impact on women’s day-to-day activities, jeopardizing their employment and academic efficiency. Yoga and pranayama are excellent non-pharmacological alternative therapies that can alleviate PMS symptoms in women. Yoga and pranayama have been shown to improve sympatho-vagal imbalance and cognitive impairments caused by a variety of aetiologies.[14,15] Previous research has found that Chandra Pranayama, Nadi Shodhana Pranayama, Bhramari, and Pranava Pranayama have parasympathomimetic effects on the autonomic nerve system. Neurocognitive benefits of Bhramari and Pranava pranayama have also been reported.[16,17] The aim of this study is to investigate the combined effect of the aforementioned pranayamas on the autonomic imbalance and cognitive deficiencies associated with PMS.

Materials and Methods

Following approval from the Institute’s scientific and ethics committee, 40 women between the ages of 18 and 45 with a regular menstrual cycle for at least 6 months and a normal BMI were recruited for the study. With a mean difference of 74 and a standard deviation of 54 from the reference article, the independent ‘t’ test formula is used to calculate sample size as 12 in each group with a type I error of 5% and a power of 90%. Given a 50% drop out rate, the sample size is rounded to 20 in each group.[10] This was a controlled, randomized trial that was registered in the Clinical trials registry India (CTRI/2020/03/024337). Age, height (cm) by stadiometer (BHH6, Easy Care, Mumbai, India), and body weight measured with minimal clothing by digital weighing machine (MS 4900, Charder Electronics Co. Ltd, Taichung, Taiwan) were measured after subjects gave written informed consent. The ‘Quetelet’s index’ was used to determine body mass index (BMI) (BMI = weight (Kg)/height² (m)²). The study participants were directed to complete the PMS Screening Tool (PSST) questionnaire, and those who met the PMS criteria were assigned to the PMS group (20 subjects) and those who did not were assigned to the non-PMS group (20 individuals). The PMS group subjects were randomly assigned to one of two groups: a pranayama intervention group (n = 10) and a no-intervention group (n = 10). Women categorized as Premenstrual Dysphoric Disorder (PMDD) using the PSST questionnaire,[18] women with menstrual cycle abnormalities, who use hormonal pills, women with history of psychological illness, hypertension, disorders of endocrine system, metabolic abnormalities, cigarette smoking, alcoholism, and women using medications that affect the autonomic nervous system and women on medications that affect cognition were excluded from the study. Following that, details of previous menstrual cycles for 6 consecutive months were collected, and the participants were asked to report during the luteal phase of their menstrual cycle (5 to 7 days before the onset of regular menstruation), at around 10.00 am, one hour after light meal. Caffeine should be avoided 12 hours before recording. Demographic data such as age, educational level, and occupation were gathered. The individuals were asked to lie supine for 5 minutes before recording lead II ECG with the BIOPAC MP100 data acquisition system (BIOPAC Inc., USA). The R-R tachogram was recovered and the values were computed using the R-wave detector in the Acknowledge software. HRV analysis software (Version 2.0., Biosignal analysis group, University of Kuopio, Finland) was used for HRV analysis. Finapres (Finometer version 1.22a, Finapres Medical Systems, Amsterdam, The Netherlands) was used to measure the BRS. The event-related potential (P300) was acquired with a Nihon Khoden EP/EMG machine and analysed with Neuropack software. P300 was captured in the context of a typical auditory oddball paradigm. The evoked responses were recorded from the scalp. Montreal cognitive assessment questionnaire (MOCA) was also administered to study participants.[13] Visuospatial, naming, memory, attention, language, abstraction, delayed recall, and orientation components have been studied in this questionnaire for a total score of 30.

Structured pranayama technique

The pranayama intervention lasted 8 weeks (5 days per week). A competent and professional yoga instructor led the course. For the first week, subjects practiced pranayama under the observation of the trainer, after which they were encouraged to practice at home, and their compliance was confirmed by a single session visit to the yoga centre around the third week of intervention and regular telephonic talk for the remaining sessions. Each session lasted around 20 minutes and included the following practices: Chandra Pranayama (9 cycles), Nadi Shodhana (9 cycles), Pranava Pranayama (5 minutes), and Bhramari (5 cycles). The following is the complete procedure for pranayama.

Chandra pranayama (9 cycles): Subjects were instructed to sit comfortably with their spines upright and shoulders relaxed. They were instructed to place the left hand on the left knee and the tip of the index finger and middle finger of the right hand in between the brows, the ring finger and little finger on the left nostril, and the thumb on the right nostril. The ring finger and little finger should be used to open or close the left nostril, and the thumb for the right nostril. The individuals were instructed to seal the right nostril and breath through the left nostril. Then they were directed told to seal left nose and breath through my right nostril.

Nadi Shodhana (9 cycles): To begin, place the thumb on the right nostril and gently breathe in through the left nostril while exhaling through the right. After each exhalation, remember to breathe in through the same nostril from which she exhaled and out through the opposite nose.

Pranava Pranayama (5 minutes): Sukhasana, ardha padmasana, or vajarasana were suggested as comfortable sitting positions for the subject. The participant was then requested to execute three rounds of slow and deep yogic breathing into the lower, middle, and upper chests, followed by a prolonged audible rendition of the akara, ukara, and makara nada (Aaa, Uuu, and Mmm sounds) during the exhale phase.

Bhramari (5 cycles): The individuals were instructed to close their eyes with four fingers over each eye and their thumbs covering their ears. The individual was then instructed to inhale deeply through both nostrils and exhale through both nostrils with the lips closed, producing a continuous humming sound until the exhalation was exhausted.

All of the parameters that were recorded before the intervention (baseline) were repeated in all three groups (No PMS group, PMS group with pranayama, and PMS group without pranayama) after 8 weeks of structured pranayama practices.

The were was entered in Microsoft Excel and analysed in IBM SPSS Statistics for Windows, Version 20.0. IBM Corp., Armonk, New York. For normally distributed parameters, the mean with standard deviation is used, whereas for non-normally distributed parameters, the median with range is used. To compare the parameters of the PMS and no PMS groups, the unpaired t test for parametric data and the Mann–Whitney U test for non-parametric data were used. In order to compare the parameters before and after intervention, for parametric data, the paired ‘t’ test was employed, and for non-parametric data, the Wilcoxan-signed rank test was utilized. Statistical significance was defined as P values less than 0.05.

Results

There was no statistically significant difference in age, BMI, systolic blood pressure, or diastolic blood pressure between the PMS and no PMS groups. Table 1 compares autonomic function and cognition parameters between PMS and no PMS groups. In PMS group’s mean HR was found to be considerably higher, RMSSD and SDNN were significantly lower. Total power was similarly lowered in the PMS group. The LF/HF ratio and LF nu were much higher in the PMS group, whereas the HF nu was significantly lower. The PMS group had a lower 30:15 ratio and an E: I ratio. The diastolic blood pressure response to isometric hand grip (Δ DBP_IHG) was higher in the PMS group. PMS patients have lower baroreflex sensitivity. P300 is prolonged in the PMS group, and MOCA scores are lowered.

Table 1.

Heart rate variability, autonomic function tests, baroreflex sensitivity and cognition parameters in PMS and no PMS group

S. no	Parameters	No PMS (n=20)	PMS (n=20)	P
TIME DOMAIN PARAMETERS
1	Mean HR	71.58±8.86	79.29±9.98	0.014*
2	RMSSDD (ms)	76.68±28	50.95±32.36	0.011*
3	SDNN (ms)	71.4 (30.5)	53.05 (26.07)	0.039*
FREQUECNY DOMAIN PARAMETERS
4	TOTAL POWER (ms2)	3151 (2024)	2220 (2001)	0.144
5	LF/HF (ms2)	0.54 (0.63)	1.16 (2.11)	0.013*
6	LF nu (ms2)	35.43 (23.53)	55.4 (38.41)	0.006*
7	HF nu (ms2)	65.56 (23.53)	44.50 (38.41)	0.006*
CARDIAC AUTONOMIC FUNCTION TEST
8	30:15 Ratio	1.24 (0.64)	1.16 (0.26)	0.135
9	EI ratio	1.51 (0.41)	1.36 (0.22)	0.008*
10	Δ DBPIHG (mmHg)	10 (3)	14.5 (5)	<0.001*
11	BRS (ms/mmHg)	22.80 (24.23)	14.8 (7.75)	0.016*
TESTS FOR COGNITION
12	P300 (ms)	293.75±35.86	358. 65±30.63	<0.001*
13	MOCA Scores	29 (1)	27 (2)	<0.001*

LFnu=Normalised low frequency, HFnu=Normalised high frequency, LF/HF=Ratio of the low frequency to the high frequency, Mean HR=Mean heart rate, RMSSD=Square root of the mean squared differences of successive normal to normal intervals, 30:15=Ratio of the maximum RR interval at 30^th beat to the minimum RR interval at 15^th beat from supine to standing, E:I=Ratio of the maximum RR interval during expiration to the minimum RR interval during inspiration following deep breathing; DBPIHG: maximum rise in diastolic BP above baseline following sustained handgrip, BRS=Baroreflex sensitivity, MOCA=Montreal cognitive assessment. Normally distributed parameters are expressed as mean±standard deviation and analysed by Independent Student ‘t’ test. Non-normally distributed parameters are expressed as median (range) and analysed by Mann Whitney U test. *P less than 0.05 are considered statistically significant.

Table 2 compares autonomic function test values, heart rate variability, and cognitive testing parameters in the PMS group before and after intervention. Following pranayama intervention, there was a substantial drop in systolic blood pressure (P = 0.003), mean HR (P = 0.008), LFnu (0.001), and Δ DBP_IHG (P = 0.007). Following pranayama intervention, SDNN (P = 0.011), RMSSD (P = 0.042), HFnu (P = 0.002), 30:15 ratio (P = 0.041), E:I ratio (P = 0.007), and Baroreflex sensitivity (P = 0.001) were observed to be considerably elevated. Following pranayama intervention, P300 (P = 0.002) was significantly lowered, and MOCA scores (P < 0.001) improved.

Table 2.

Comparison of pre and post-intervention parameters in PMS group

S.no	Parameter	Baseline	After 8 weeks	P	Baseline	After 8 weeks	P
		Intervention group (n=10)			No intervention group (n=10)
1	Systolic Blood Pressure (mm Hg)	124.9±18.5	110.7±14	0.003*	118±14.3	120.9±15.1	0.298
2	Diastolic blood pressure (mm Hg)	67.6±11.2	63±6.9	0.155	60.8 (45)	63 (43)	0.06
TIME DOMAIN PARAMETERS
3	Mean HR	81.7±12.9	74.4±10.7	0.008*	77.8 (36.4)	77.8 (27.9)	0.28
4	SDNN (ms)	69±30.5	95.4±37.1	0.011*	50.7 (80.1)	50.2 (77.1)	0.507
5	RMSSD (ms)	51.1±34	72.8±44.4	0.042*	45.1 (115.3)	46.2 (112.1)	0.656
FREQUENCY DOMAIN PARAMETERS
6	Total Power (ms2)	1853 (9723)	1978 (9977)	0.5	2162 (7371)	2191 (7348)	0.285
7	LF nu (ms2)	53.7±21.3	40.9±22.8	<0.001*	55.8±17.5	55.7±17.3	0.86
8	HF nu (ms2)	48.4±22.4	58.6±22.6	0.002*	44.1±17.5	44.2±17.3	0.86
9	LF/HF	1.07 (5.6)	0.4 (2.6)	0.2	1.4 (3.7)	1.4 (3.8)	0.374
CARDIAC AUTONOMIC FUNCTIONS
10	30:15 Ratio	1.1±0.2	1.2±0.17	0.041*	1.1±0.12	1.2±0.11	0.26
11	E:I ratio	1.3±0.2	1.5±0.2	0.007*	1.3±0.09	1.3±0.08	0.95
12	Δ DBPIHG (mmHg)	16±7.7	11.2±4.2	0.007*	14.4±3.9	14.5±3.9	0.79
BAROREFLEX SENSITIVITY
13	BRS (ms/mmHg)	14±7.8	27±14.6	0.011*	15.5±4.6	15.±5.01	0.21
COGNITION
14	P300 (ms)	357.7±36.3	318.8±44.8	0.002*	358±24.7	359±25.3	0.249
15	MOCA scores	26±1	29±0.5	<0.001*	26.9±2.8	27.3±2.8	0.676

LFnu=Normalised low frequency, HFnu=Normalised high frequency, LF/HF=Ratio of the low frequency to the high frequency, Mean HR=Mean heart rate, SDNN=Standard deviation of the averages of the NN intervals in all 5 min segments, RMSSD=Square root of the mean squared differences of successive normal to normal intervals, 30:15=Ratio of the maximum RR interval at 30^th beat to the minimum RR interval at 15^th beat from supine to standing, E:I=ratio of the maximum RR interval during expiration to the minimum RR interval during inspiration following deep breathing, DBPIHG=Maximum rise in diastolic BP above baseline following sustained handgrip, BRS=Baroreflex sensitivity, MOCA=Montreal cognitive assessment. *P values less than 0.05 are considered statistically significant. Normally distributed parameters are expressed as mean±standard deviation and analysed by Paired ‘t’ test. Non- normally distributed parameters are expressed as median (range) and analysed by Wilcoxon signed ranks test.

Discussion

The effect of structured pranayama techniques on cardiac autonomic functioning, cognition, and baroreflex sensitivity in PMS was investigated in the current study. We have recruited 20 women with PMS and 20 women who do not have PMS. We matched the groups based on age and BMI because age and BMI affect autonomic functions and cognition. When compared to women without PMS, women with PMS had higher sympathetic activity and decreased parasympathetic activity, according to our findings. Our findings supported prior research that found sympathetic overactivity in women with PMS during the late luteal phase of the menstrual cycle.[2,6] In the PMS group, persistent sympatho-vagal imbalance can predispose to cardiovascular risk. In our study, we observed that the cognition of the PMS group was lower than that of the non-PMS group. This decreased cognition is due to progesterone’s inhibitory influence on neuronal activity.[1,19] Previously, no consistent results of reduced cognition in PMS have been found in studies. So the novelty of our study is that we found considerable cognitive impairment in PMS patients. There have also been no previous research that reveal the benefits of pranayama techniques on autonomic imbalance and cognition in PMS. Although there are various therapeutic options for PMS, such as lifestyle changes, psychological therapies, and pharmaceutical therapies, none of these modalities provide total relief of premenstrual symptoms.[20] Because the symptoms of PMS are attributed to sympathetic overactivity in the late luteal phase of the menstrual cycle and autonomic imbalance is also associated with cognitive impairment, yoga and pranayama practices that have been shown to have beneficial effects on cardiac autonomic functions can be used in the management of premenstrual symptoms.[7,21] In our study, systolic blood pressure, Mean HR, LF nu, LF/HF ratio, Δ DBP_IHG, and P300 latency were considerably lowered, whereas Total power, HF nu, SDNN, RMSSD, HFnu, 30:15 ratio, E:I ratio, and MOCA score were significantly improved after 8 weeks of pranayama practice. Sympathetic activity is denoted by LFnu, sympathovagal imbalance by LF: HF, and parasympathetic activity by HFnu.[22] The most sensitive time domain HRV parameters are SDNN and RMSSD. The post-pranayama values of LFnu, Total Power, SDNN, and RMSSD in our investigation indicate parasympathetic dominance. The rise in cardiac autonomic function indices 30:15 ratio and E:I ratio in our trial further demonstrates the parasympathetic influence of the pranayama techniques used. The pranayama practices also significantly improved cognition, as evidenced by lower P300 latency and higher MOCA scores. Following 8 weeks of pranayama instruction, study participants reported subjective improvement in PMS psychosomatic symptoms as measured by the PSST questionnaire.

Conclusion

In India, the prevalence of PMS ranges from 14.3% to 74.4%.[23] The PMS significantly takes a toll on health and wellbeing of women in their reproductive age. Autonomic imbalance in women in PMS also predisposes them to long-term cardiovascular morbidity. Pranayama can be used as an effective and safe non-pharmacological modality in relieving the symptoms of PMS, thereby improving the quality of life of women.

Limitation

Due to cost constraints, the sex steroid levels could not be estimated. Our study only demonstrated the short-term impact of pranayama practices on PMS; further research needs to be conducted to evaluate their long-term effects.

List of abbreviations

• PMS - Premenstrual Syndrome

• CAFT - Cardiovascular Autonomic Function Tests

• HRV - Heart Rate Variability

• BRS - Baroreflex Sensitivity

• ERP - Event Related Potential

• MOCA - Montreal cognitive assessment

• BMI - Body mass index

• PSST - Premenstrual Syndrome Screening Tool

• PMDD - Premenstrual Dysphoric Disorder

• RMSSD - Square root of the mean squared differences of successive normal to normal intervals

• SDNN - Standard deviation of the averages of the NN intervals in all 5 min segments

• IHG - Isometric Handgrip

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.